The rod may become incandescent (3-3)
I believe the answer is:
red-hot
'incandescent' is the definition.
(I've seen this before)
'the rod may become' is the wordplay.
'may become' indicates an anagram.
'the'+'rod'='therod'
'therod' with letters rearranged gives 'RED-HOT'.
(Other definitions for red-hot that I've seen before include "Flower (just out of the fire?)" , "Very heated, popular" , "likely to win" , "Glowing; extremely popular" , "Glowing fiercely" .)